om his pocket and calculated the time that had
elapsed since Professor Dahlgren had vanished from that same spot.
Nearly forty hours. That would mean....

Nanette stirred in her chair. "What happened to the little rat,
Aaron?"

Carruthers, busy making calculations, did not hear the question.

She turned to her brother. "Karl, what's the meaning of this? The
second experiment didn't turn out like the first one. What became of
that little rat?"

"I don't know what happened, Nan," spoke Karl. "Now don't bother me
with your silly questions. You saw the same thing I did."

* * * * *

Carruthers raised his head and spoke quietly. "That rat you saw
materialize under the atomic rays was the same rat you saw me place
within the square."

"But it couldn't be," protested the girl.

"Nevertheless," shrugged Carruthers. "It was the same animal--only it
had aged nearly two years during the brief time interval it was off
from our planet."

"It's preposterous," cried the girl.

"Nothing is preposterous nowadays, Nanette."

"That's the woman of it," spoke Karl. "Always doubting."

"You boys are playing tricks on me," retorted the girl sharply. "I
shouldn't have come to your old laboratory. Just because I'm a
girl...."

"Don't," pleaded Carruthers, looking up from his pad of figures.
"We're trying to solve the mystery underlying the forces which we have
created." He replaced the test tube within the center of the square
and returned to the atomic machine.

Through the twilight shadows of the room glowed the strange new ray.
Faintly the generator hummed. Lights sparkled and twisted around the
cathode in serpentine swirls.

"You needn't trouble to explain your silly experiment again," finished
Nanette, rising abruptly to her feet. "I'm going home and dress for
the New Year's party."

"Watch your switch like I asked you to," spoke Carruthers.

"Sit down," added Karl. "Don't put the rest of us in danger!"

"Oh-h-h!" gasped the girl as she inadvertently stepped squarely into
the atomic ray of amber-colored light.

* * * * *

Carruthers leaped impatiently to his feet. An inarticulate cry of
horror froze upon his lips. Forgetful that he himself was directly in
line of the atomic ray he lunged forward, his mind centering on a
single act--to drag the protesting and now thoroughly frightened girl
out of the path of the penetrating ray.

But even as he starte